256 RITTER 



with about twenty stigmata in each half series ; the individual stigmata 

 when fully grown about four times as long as broad ; border cells dis- 

 tinct. Interserial spaces narrow and without muscle fibers. Three 

 internal longitudinal bars on each side. The dorsal lamina, as seen 

 through the animal, a plain narrow membrane, resembling one of the 

 internal longitudinal vessels. 



Digestive apparatus. — Situated on the left side of and projecting 

 but very slightly behind the branchial sac at the posterior end. Esoph- 

 agus issuing from the postero-dorsal angle of the sac; nearly as long 

 as the stomach. Stomach situated nearly transversely to the sac, and 

 extending somewhat more than half way across it, having its pyloric 

 and cardiac ends about equally remote from the dorsal lamina and 

 endostyle respectively. Stomach about one-third longer than broad ; 

 slightly curved, the convex side looking backward. Wall with about 

 eight or ten double folds which extend the entire length of the organ. 

 The intestine behind the stomach in the form of an open S, with the 

 rectal limb considerably longer than the pyloric and quite straight. 

 The rectum reaching forward in the cloaca anterior to the middle of 

 the sac. Anus usually showing more or less of a lip. The post-gas- 

 tric intestine nearly uniform in diameter throughout. 



Reproductive apparatus. — Gonads on both sides of the body ; im- 

 mature and very small in all the material at hand. Budding zooids 

 abundant ; two buds, one on each side, on each budding individual. 



The specific character particularly relied upon for this form, viz, 

 the large size of the zooids, is a strong point in favor of regarding it as 

 belonging not to Botryllus at all, but to Polycychis., and I am much 

 inclined to believe that its closest affinities are in reality with P. Sa- 

 vignyi Herdman. According to prevailing views regarding the gen- 

 eric characters of the Botryllida^, however, the comparative thinness 

 of the colony and the softness of the test require that it be placed in 

 the genus Botryllus. The large size of the zooids, the uniformity of 

 color of the colonies, and the relative nearness of the atrial to the 

 branchial siphon make it a rather distinct species in this genus. 



A single colony dredged in about 20 fathoms at Kadiak Island ; 

 about a half dozen colonies found on rocks at low tide at Popof Island, 

 Shumagin Islands, July S, 1S99. 



